1. Field of the Invention
This invention relates to a protective metal housing for enclosing a plastic air admittance valve of the type described in U.S. Pat. No. 4,535,807, the disclosure of which is herein incorporated by reference.
2. Description of the Prior Art
Plastic air admittance valves of the type referred to above are widely employed as vent terminals in the sewer vent lines of private dwellings and similar sized buildings. However, the installation of such valves in large commercial building, e.g., multi-dwelling housing complexes, commercial high rise buildings, etc., has been largely restricted by building codes that prohibit the use of exposed plastic components in plumbing systems, including the vent lines associated with such systems.
The objective of the present invention is to enclose the plastic air admittance valves in specially configured protective metal housings, thus satisfying commercial code restrictions, without in any way compromising the function of the valves as efficient vacuum breakers.
In accordance with a preferred embodiment of the invention, the protective housing includes a cylindrical adaptor and a cover. The adaptor has a through passage internally threaded for connection at one end to a sewer vent pipe or the like, and for connection at the opposite end to an externally threaded stem projecting downwardly from the vacuum breaker valve head. The cover is structured and dimensioned to coact with the adaptor in defining an enclosed chamber for containing the valve head.
The cover is removably secured to the adaptor, and is provided with inlet openings arranged to expose the valve head to ambient air.
These and other features and advantages of the present invention will now be described in greater detail with reference to the accompanying drawings, wherein: